1. Field of the Invention
The invention relates to rotation angle detection devices.
2. Description of the Related Art
Conventionally, a resolver having a shaft angle multiplier of 1× is known as an example of rotation angle detection devices that detect the rotation angle (mechanical angle) of a motor mounted on automobiles or electric apparatuses. The resolver having a shaft angle multiplier of 1× outputs an electrical signal whose electrical angle (phase of an output signal) changes by one period for one period (360 degrees) of a mechanical angle. As described in Japanese Patent Application Publication No. 2012-202906 (JP 2012-202906 A), a rotation angle detection device is proposed which includes a resolver and a magnetoresistive (MR) sensor in order to improve redundancy and in which the difference in shaft angle multiplier between the resolver and the MR sensor is set to 1.
Although there are various types of rotation angle detection devices including the above rotation angle detection device, the demands for the devices such as detection accuracy and product cost have been increasingly diversified in recent years. Technical development has been done in a broad range of areas in response to these demands.